In science, you could post articles and have students respond to them. See the example below: Nuclear Energy Debate
They could then also respond to what other students said.
The students could create reports using their own wikipages. Other students in your class, or other class periods, could view them and comment on them.
The students could create banks of knowledge. You could start a wikipage about local plants. Students could research various plants, where they are found, uses, pictures, etc and add them to your wikipage. Other students could then use this bank to learn more about the plants in the area. They could even respond with information they discover or know about someone else's plant.
Nuclear Energy Debate
They could then also respond to what other students said.
The students could create reports using their own wikipages. Other students in your class, or other class periods, could view them and comment on them.
The students could create banks of knowledge. You could start a wikipage about local plants. Students could research various plants, where they are found, uses, pictures, etc and add them to your wikipage. Other students could then use this bank to learn more about the plants in the area. They could even respond with information they discover or know about someone else's plant.
The possibilities are endless. If you want help developing a lesson using wikipages, see me, or go to http://wikispaces.com/site/for/teachers.
Online Resources
Myth Busters http://school.discoveryeducation.com/teachers/myth-busters/ - Need I say more
Game Templates for Science http://jc-schools.net/tutorials/PPT-games/ - Use with interactive white boards
Invention Studio http://multimedia.discovery.com/mms/inventionstudio/inventionstudio.html - Design, Build and Test real inventions
Net Frog http://frog.edschool.virginia.edu//home.html - Online dissection